Self-loading scrapers which are provided with a generally upright auger near the cutting edge of the scraper bowl are well known as disclosed in U.S. Pat. Nos. 3,857,190, 3,863,367, and a number of earlier patents. The auger helps to prevent jamming of material in the front of the bowl by moving some of it upwardly so that it may fall behind the auger. Such augers commonly have a shaft mounted in a bearing at the bottom of the bowl, while there is a driving connection between the upper end of the auger shaft and an auger drive means which is mounted upon a cross beam at the top of the bowl as disclosed in said U.S. Pat. No. 3,863,367.
The supporting bearing assembly for the auger in a self-loading scraper bowl operates in an extremely dirty environment, where it is constantly subjected to the action of masses of moving material that varies from the finest soil, which may be either powder dry or suspended in water, to rocks and boulders. Accordingly, a conventional seal of the type that surrounds a rotating shaft must function under the severest possible conditions to keep abrasive material out of the bearings.
In addition, the mounting of an auger shaft between a lower bearing in the bottom of a scraper bowl and drive connection on a motor shaft at the top of the scraper bowl requires precise alignment between the motor shaft and the bearing housing because of the need for precision mounting of the lower end of the auger shaft in the bearing.
Furthermore, auger scrapers may be used for loading coal, rock and rubble that includes stones of substantial size; and a rock which is large enough to jam between the lower end of the auger flight and the bearing can cause severe damage to one or more of the bearings, the auger or the drive means.